Methods and pharmaceuticals for treatment of viral infections of the eye

ABSTRACT

Viral infections of the eye, and particularly viral infections in the Herpesviridae and Adenoviridae families, can be treated by administration of a pharmaceutical made up of an enzymatically active ribonuclease and a vehicle. Advantageously, the enzymatically active ribonuclease is ranpirnase, the &#39;805 variant, rAmphinase 2, and Amphinase 2, and the vehicle is an aqueous solution.

BACKGROUND OF THE INVENTION

The invention relates to viral infections of the eye, and more particularly relates to methods and pharmaceuticals for treatment of viral infections of the eye. In its most immediate sense, the invention relates to treatment of human eye infections caused by Herpesviridae viruses (including but not limited to Human cytomegalovirus, herpes zoster virus, and varicella zoster virus) and Adenoviridae viruses.

Viral diseases of the eye can have significant consequences. Type 1 herpes simplex virus can cause conjunctivitis and keratitis, Human cytomegalovirus can cause retinitis, adenovirus types 8, 19, 29, and 37 can cause epidemic keratoconjunctivitis, and adenovirus types 3, 4, and 7 can cause pharyngoconjuctival fever. Herpes zoster virus (HZV), a member of the Herpesviridae family, can cause severe eye disease when affecting the trigeminal area. Herpes zoster ophthalmicus, a severe form of acute herpes zoster, results from the reactivation of varicella zoster virus (VZV) (another member of the Herpesviridae family) in the trigeminal (fifth cranial) nerve. Any branch of the nerve may be affected, though the frontal branch within the first division of the trigeminal nerve is most commonly involved. This frontal branch innervates nearly all of the ocular and periocular structures. Herpes zoster ophthalmicus at this particular location can lead to blindness and requires a fast and effective therapeutic approach.

Human cytomegalovirus (CMV) is another member of the Herpesviridae family. At least 60% of the US population has been exposed to CMV, with a prevalence of more than 90% in high-risk groups (e.g., unborn babies whose mothers become infected with CMV during pregnancy, people with HIV, and transplant recipients).

CMV retinitis is one of the most common opportunistic infections in persons with AIDS or pharmacologically induced immunosuppression. Individuals with CMV retinitis typically exhibit a progressive decrease in visual acuity, which may progress to blindness. Long-term CMV treatment is necessary to prevent retinitis relapse.

Immune reconstitution syndrome (IRIS) is reported in 16%-63% of HIV-infected patients with CMV retinitis following the initiation of HAART (Highly Active Antiretroviral Treatment). CMV IRIS may manifest as painless floaters, blurred vision, photopia, decreased visual acuity, or ocular pain. Some patients may develop macular edema leading to vision loss or proliferative vitreoretinopathy, spontaneous vitreal hemorrhage, and retinal detachment.

It is known to treat viral eye infections with acyclovir but such treatment is not entirely satisfactory. Topical acyclovir must be applied frequently and causes irritation of the eye. Oral acyclovir causes significant adverse side effects. Other antiviral medications such as gancyclovir, valacyclovir and valgancyclovir are used to treat viral eye infections, and such treatments are also not entirely satisfactory. Gancyclovir is administered intravenously, and therefore cannot be used outside e.g. a hospital setting. Oral antiviral medications such as valacyclovir and valgancyclovir have disadvantages; they are known to cause fever, rash, diarrhea, and hematologic effects (e.g., neutropenia, anemia, thrombocytopenia). In some cases neutropenia may respond to lowering the dose or using drugs that stimulate the production of neutrophils by the bone marrow as granulocyte colony-stimulating factor [G-CSF], or granulocyte-macrophage colony-stimulating factor [GM-CSF]. These toxic effects can be difficult to manage.

It would therefore be advantageous to provide a better method and a better pharmaceutical for treating viral eye infections in humans.

Various enzymatically active ribonucleases, including ranpirnase and other proteins that are highly homologous to it, are known to have antiviral activity, and to have activity against viruses in the Herpesviridae family (specifically including but not limited to Herpes simplex virus types 1 and 2 and Human cytomegalovirus) and also against type 2 adenovirus. However, proteins are known to be highly irritating to the eye due to an intense inflammatory response mediated by T-cells. For this reason, although ranpirnase and other related proteins have been investigated for use against various viral infections, they have not been investigated for use against viral infections of the eye.

Despite the expectation that proteinaceous ranpirnase would cause irritation in the eye, irritation of topically applied ranpirnase in the eye was studied in a rabbit model. In this experiment, ranpirnase was demonstrated to be non-irritating as determined using the Globally Harmonized System of Classification Evaluation Criteria and the European Economic Community Ocular Evaluation Criteria. This was a remarkable result, because administration of a foreign protein to the eye can produce corneal irritation. As a result, ranpirnase and other proteins that are highly homologous to it are expected to be useful in treating viral infections of the human eye.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood with reference to the following exemplary and non-limiting drawings, in which:

FIG. 1 shows the scale used for scoring ocular lesions observed in a rabbit that has undergone a Draize test;

FIG. 2 shows the results of a Draize test in which a ranpirnase solution was applied to the right eye of three rabbits;

FIG. 3 shows the results of the Draize test of FIG. 2 in which the left eye of each of the rabbits was untreated; and

FIG. 4 shows the European Economic Community Ocular Evaluation Criteria used to classify the ocular irritation caused by a test article in a Draize test.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Ranpirnase is a proteinaceous enzymatically active ribonuclease (the word “ribonuclease” is frequently abbreviated as “RNase”) that is disclosed and claimed in U.S. Pat. No. 5,559,212. U.S. Pat. Nos. 5,728,805, 6,239,257, 7,229,824 and 8,518,399 disclose three other proteinaceous enzymatically active ribonucleases that are highly homologous to ranpirnase:

-   -   a) the ribonuclease of SEQ ID NO:2 in U.S. Pat. No. 5,728,805,         herein referred to as the “'805 variant”;     -   b) the ribonuclease of SEQ ID NO:2 in U.S. Pat. No. 6,239,257,         herein referred to as “Amphinase 2”, and;     -   c) the ribonuclease of SEQ ID NO:59 of U.S. Pat. No. 7,229,824,         herein referred to as “rAmphinase 2”.

U.S. Pat. No. 8,518,399 discloses that ranpirnase, the '805 variant, and rAmphinase 2 have antiviral activity against Herpesviridae viruses, specifically including but not limited to Herpes simplex types 1 and 2 and Human cytomegalovirus. Based upon its similarities with these three enzymatically active ribonucleases, it is believed that Amphinase 2 will have these activities as well.

Commonly-owned copending patent application Ser. No. 14/736,170 filed Jun. 10, 2015 and published as US 2015/0376584 A1 discloses that ranpirnase has antiviral activity against a number of viruses, including type 2 adenovirus. As stated therein, the viruses in the Adenoviridae family are very closely related and the demonstrated antiviral activity of ranpirnase against any one virus within the Adenoviridae family is strong evidence that ranpirnase will have the same anti-replication activity against all viruses within the Adenoviridae family. Furthermore, as stated in that pending patent application, to a person of ordinary skill in this art, the similarities of homology and activity of these three other ribonucleases is strong evidence that these three other ribonucleases will have the same activity as ranpirnase has. Hence, although in vitro experiments have not yet been repeated using the '805 variant, Amphinase 2, or rAmphinase 2, a person of ordinary skill in this art would conclude that these three ribonucleases will likewise be active against all the viruses in the Adenoviridae family.

Thus, ranpirnase, the '805 variant, Amphinase 2, and rAmphinase 2 have either been demonstrated to be active against type 1 Herpes simplex virus and viruses in the Adenoviridae family or would be expected to be so active. For this reason, a person of ordinary skill in the art would expect that all four of these proteinaceous enzymatically active ribonucleases will be useful against viral infections of the human eye.

All four of these ribonucleases are members of the ribonuclease A superfamily. Such ribonucleases are pyrimidine-specific endonucleases found in high quantity in the pancreas of certain mammals and of some reptiles. They are involved in endonucleolytic cleavage of 3′-phosphomononucleotides and 3′-phosphooligonucleotides ending in C-P or U-P with 2′,3′-cyclic phosphate intermediates. Other members of this superfamily include bovine seminal vesicle and brain ribonucleases, kidney non-secretory ribonucleases, liver-type ribonucleases, angiogenin; eosinophil cationic protein, pancreatic ribonucleases from different species including human, and bovine pancreatic ribonucleases.

Ranpirnase, which is disclosed in U.S. Pat. No. 5,559,212, and was previously known by the ONCONASE trademark, is a ribonuclease isolated from oocytes of the leopard frog Rana pipiens. The amino acid sequence of ranpirnase is provided in SEQ ID NO: 1. Ranpirnase has been tested and found to be cytotoxic to cancer cells because of its enzymatic activity against RNA.

A variant of ranpirnase (hereinafter, the “'805 variant”) is disclosed in U.S. Pat. No. 5,728,805. The '805 variant is also a ribonuclease, and has likewise been found to be cytotoxic to certain cancer cells. The '805 variant is a close variant of ranpirnase; its amino acid sequence is identical to that of ranpirnase except that it has valine instead of isoleucine at position 11, asparagine instead of aspartic acid at position 20, and arginine instead of serine at position 103 of the ranpirnase amino acid sequence. The '805 variant has been referred to as “Val11, Asn20, Arg103-Ranpirnase”. The amino acid sequence of the '805 variant is provided in SEQ ID NO:2.

Amphinase 2 is also a ribonuclease. It is the protein identified as 2325p4 in U.S. Pat. No. 6,239,257 and it too has been found to be cytotoxic to cancer cells. The amino acid sequence of Amphinase 2 is provided in SEQ ID NO: 3.

Recombinant Amphinase 2 (“rArphinase 2”) is similar to Amphinase 2, but has a Met residue at position −1 and lacks glycan moieties that are located in Amphinase 2 at positions 27 and 91. rAmphinase 2 is described in U.S. Pat. No. 7,229,824. The amino acid sequence of rAmphinase 2 is provided in SEQ ID NO: 4.

The term “functional equivalent” is intended to mean any protein that differs from any naturally occurring ribonuclease by the deletion, addition or substitution of one or more amino acids, but that retains ribonuclease activity. For example, the '805 variant is a functional equivalent of ranpirnase, because it comprises three amino acid substitutions compared to the ranpirnase amino acid sequence, but still has RNase activity.

The disclosures of U.S. Pat. Nos. 5,559,212, 5,728,805, 6,239,257, 7,229,824, 8,518,399, 8,663,964 and published patent application US 2015/0376584 A1 are all incorporated by reference herein in their entireties for all purposes.

As discussed above, it has been found that a ribonuclease of the RNase A superfamily, in particular ranpirnase, can be used in the treatment of a viral infection of the eye. A “viral infection of the eye” is a disease which shows symptoms predominantly in the eye of a subject and which is caused by viruses rather than bacteria. Viral diseases of the eye include, but are not limited to, conjunctivitis and keratitis, retinitis, keratoconjunctivitis, chorioretinitis, pharyngoconjuctival fever and CMV retinitis.

Viral conjunctivitis, also known as pink eye, is characterized by inflammation of the outermost layer of the white part of the eye and the inner surface of the eyelid. Viral conjunctivitis is typically caused by an adenovirus. Other viruses that can be responsible for conjunctival infection include herpes simplex virus (HSV), varicella-zoster virus (VZV), enterovirus 70, Coxsackie virus A24, molluscum contagiosum and human immunodeficiency virus (HIV).

Viral keratitis is an inflammation of the cornea which is predominantly caused by herpes simplex virus.

Chorioretinitis is an inflammation of the choroid (thin pigmented vascular coat of the eye) and retina of the eye. It is a form of posterior uveitis. Chorioretinitis can be caused by infection with cytomegalovirus (CMV), Varicella-Zoster (HZV), dengue fever, West Nile virus or lymphocytic choriomeningitis virus (LCMV).

In particular, viral infections of the eye can be caused by a virus from the Herpesviridae family of viruses and by an adenovirus selected from the group consisting of 3, 4, 7, 8, 19, 29, and 37.

Herpesviridae are viruses having a double-stranded, linear DNA genome which are classified in Baltimore class I. Viruses from the Herpesviridae family causing viral infections of the eye include, but are not limited to, type I Herpes simplex virus, human cytomegalovirus and Herpes zoster virus, in particular Herpes zoster ophthalmicus.

Adenoviridae are double-stranded DNA viruses which are classified in Baltimore class I. Adenovirus types 8, 19, 29, and 37 can cause epidemic keratoconjunctivitis, and adenovirus types 3, 4, and 7 can cause pharyngoconjuctival fever types 8, 19, 29, and 37 can cause epidemic keratoconjunctivitis, and Adenovirus types 3, 4, and 7 can cause pharyngoconjuctival fever.

The terms “treating” and “treatment,” as used herein, refer to administering to a subject having a viral infection of the eye a therapeutically effective dose of a ribonuclease such as ranpirnase, a ranpirnase variant such as the '805 variant, Arnphinase 2, or rAmphinase 2. As used herein, the term “treating” covers any treatment of a viral infection of the eye which results in a desired pharmacologic and/or physiologic effect, including arresting disease development, causing regression of the disease, limiting spread of the virus from one cell to another within an individual, limiting replication of a virus in an individual, limiting entry of a virus into the cell of an individual and reducing the number of viruses in an individual or a tissue of this individual.

The term “therapeutically effective dose” refers to an amount of a pharmaceutical that results in an improvement or remediation of the symptoms of a disease or condition to be treated. A therapeutically effective dose of a ribonuclease such as ranpirnase, '805 variant, Amphinase 2, or rAmphinase 2, delays or minimizes the onset of, or hastens or increases recovery of a subject from, a viral infection of the eye in a subject. The RNase may reduce the viral titer in the eye of the infected subject, or may prevent the viral titer in the eye of the infected subject from increasing. A therapeutically effective dose of a ribonuclease may provide a therapeutic benefit in the treatment or management of a viral infection of the eye by reducing the spread of the virus from one cell to another and may also prevent disease and/or reduce the severity of symptoms.

A therapeutically effective dose can be determined by the skilled person as a matter of routine experimentation. The therapeutically effective dosage of the pharmaceutical composition can be determined readily by the skilled artisan, for example, from animal studies. In addition, human clinical studies can be performed to determine the preferred effective dose for humans by a skilled artisan. Such clinical studies are routine and well known in the art. The precise dose to be employed will also depend on the route of administration. Effective doses may be extrapolated from dose-response curves derived from in vitro or animal test systems.

The RNase may be administered to a subject in need thereof in a single dose or in multiple doses. The RNase may be administered to the subject until symptoms resolve and/or until the subject is no longer at risk of a virus infection. The schedule on which the administration of the RNase (advantageously, ranpirnase) commences, and on which a single dose or multiple doses of the RNase (advantageously, ranpirnase) is or are administered to the subject, and the duration of dosing, can be determined by a person of ordinary skill. These factors may depend on factors such as the severity of symptoms, patient response, etc.

The administration of a therapeutically effective dose of the RNase (advantageously, ranpirnase) may reduce the virus titer in the eye compared to a control that is infected with the virus but not treated with the RNase.

The administration of a therapeutically effective dose of the RNase (advantageously, ranpirnase) may lead to a reduction of the virus titer below the detection level. Determination of virus titers is for example discussed in Reischl (1996) Front Biosci. 1:e 72-7, Application of molecular biology-based methods to the diagnosis of infectious diseases.

The ribonuclease (advantageously, ranpirnase) is preferably administered topically to the eye, i.e. is administered directly to the eye and not elsewhere on the body. The topical administration may be by e.g. eye drops, a suspension, an emulsion, an ointment, a solution, a gel, liposomes, nanoparticles, microemulsions, nanoemulsions, nanosuspensions, niosomes, dendrimers and hydrogels. Alternatively, the ribonuclease (advantageously, ranpirnase) may be administered by the intravitreal, intracameral, subconjunctival, subtenon, retrobulbar or posterior juxtascleral route.

The ribonuclease will be a component of a pharmaceutical that includes a vehicle. The term “vehicle” includes any and all solvents, dispersion media, coatings, antibacterial and antifungal agents, isotonic and absorption delaying agents and the like. The use of such media and agents for pharmaceutically active substances is well known in the art. These agents are generally safe, non-toxic and neither biologically nor otherwise undesirable.

The vehicle may contain ingredients such as an excipient, a surfactant, an ingredient to adjust the pH of the composition and to buffer within a certain pH range, and a tonicity agent to adjust the tonicity of the composition. Such ingredients are known, and persons of ordinary skill in the art can select such of them as will produce a formulation having appropriate characteristics when combined with the RNase (advantageously, ranpirnase).

It is possible to determine whether a substance (here, a ribonuclease) is non-irritating to the eye in a Draize test using the Globally Harmonized System of Classification Evaluation Criteria and using the European Economic Community Ocular Evaluation Criteria. In the Draize test the RNase is placed in the conjunctival sac of a rabbit's eye and the eye is examined at 1, 24, 48 and 72 hours after instillation of ranpirnase. The criteria evaluated are corneal opacity, iris lesion, conjunctival redness and conjunctival edema. If the score for each of these criteria is zero, the tested substance is considered non-irritating to the eye. FIGS. 1 and 4 show, respectively, the scale used for scoring ocular lesions observed in a rabbit that has undergone a Draize test and the European Economic Community Ocular Evaluation Criteria used to classify the ocular irritation caused by a test article in a Draize test.

As stated above, before the present invention, no person of ordinary skill in the art would administer to the eye ranpirnase or any of the other three above-identified proteinaceous enzymatically active ribonucleases. However, such administration of ranpirnase has been modeled using the Draize test and the results of this experiment demonstrate that ranpirnase is non-irritating as defined by two accepted standards.

Example

A 0.1% mL solution made up of 0.1% ranpirnase in a proprietary aqueous solution used as a vehicle was used as a test article. Three rabbits were used; each was a male New Zealand White rabbit that was approximately 16 weeks old at the time of the experiment and that weighed 3.3 to 3.4 kg.

After administration of two drops of Tetracaine pre-anesthetic to the corneal surface of both eyes of each rabbit, the test article was placed in the conjunctival sac of the right eye of each rabbit by gently pulling the lower lid away from the eyeball; the lids were gently held together for approximately one second to limit the loss of the test material. The left eye of each rabbit remained untreated and served as the control. The eyes of the animals were examined at 1 (+15 minutes), 24, 48, and 72 hours (±1 hour) after installation of the test article. The grades of ocular reaction according to Draize (FIG. 1) were manually recorded at each examination (FIGS. 2 and 3). As can be seen in FIG. 2, there was an ocular reaction in each animal one hour post-instillation of the test article but in every instance that reaction was completely resolved by 24 hours and thereafter.

To determine the degree of irritation caused by the test article using the European Economic Community Ocular Evaluation Criteria (FIG. 4), the total ocular irritation scores for the examinations at 24, 48, and 72 hours were individually added for corneal opacity, iris lesion, conjunctival redness, and conjunctival edema and the mean scores for these scoring parameters were compared to the European Economic Community Ocular Evaluation Criteria. Because all these scores (and therefore the calculated mean scores) were zero, the test subject was considered to be non-irritating as defined by the European Economic Community Ocular Evaluation Criteria.

To determine the degree of irritation caused by the test article using the Globally Harmonized System of Classification Evaluation Criteria, the 24-, 48-, and 72-hour scores were added separately for each animal and each total divided by 3 (three time points) to yield the individual mean scores for each animal. Because all these scores (and therefore the calculated quotients) were zero, the test subject was considered to be non-irritating as defined by the Globally Harmonized System of Classification Evaluation Criteria.

Hence, these test data demonstrate a new and unexpected result: ranpirnase delivered to the eye in an aqueous solution is non-irritating as defined by the Globally Harmonized System of Classification Evaluation Criteria and by the European Economic Community Ocular Evaluation Criteria, even though ranpirnase is a protein (which would be expected to be irritating to the eye).

Although this experiment was carried out using a solution of ranpirnase in a proprietary aqueous vehicle, a person of ordinary skill in the art would consider it likely that solutions of the three above-identified proteinaceous enzymatically active ribonucleases would behave in the same way because of their similarities to ranpirnase in respect of activity and homology.

Although at least one preferred embodiment of the invention has been described above, this description is not limiting and is only exemplary. The scope of the invention is defined only by the claims, which follow: 

1. A method of treating a herpesviral infection of the eye, comprising the step of administering to the eye a therapeutically effective dose of a ribonuclease that is a member of the ribonuclease A superfamily.
 2. The method of claim 1, wherein the eye is a human eye and the ribonuclease is selected from a group consisting of a. ranpirnase; b. the '805 variant; c. Amphinase 2; and d. rAmphinase
 2. 3. The method of claim 1, wherein the ribonuclease is non-irritating to the eye as determined using a. the Globally Harmonized System of Classification Evaluation Criteria and b. the European Economic Community Ocular Evaluation Criteria.
 4. The method of claim 1, wherein the eye is a human eye and the ribonuclease is functionally equivalent to a ribonuclease selected from a group consisting of: a. ranpirnase; b. the '805 variant; c. Amphinase 2; and d. rAmphinase
 2. 5. A method for treating a herpesviral infection of the human eye, the method comprising administering an ophthalmic composition to the eye, the composition comprising: a. a therapeutically effective dose of a ribonuclease that is a member of the ribonuclease A superfamily and that is non-irritating to the eye as determined using i. the Globally Harmonized System of Classification Evaluation Criteria and ii. the European Economic Community Ocular Evaluation Criteria; and b. a vehicle.
 6. The method of claim 5, wherein the ribonuclease is selected from a group consisting of: a. ranpirnase; b. the '805 variant; c. Amphinase 2; and d. rAmphinase
 2. 7. The method of claim 5, wherein the vehicle is an aqueous solution.
 8. The method of claim 5, wherein the ribonuclease is the functional equivalent of a ribonuclease selected from a group consisting of a. ranpirnase; b. the '805 variant; c. Amphinase 2; and d. rAmphinase
 2. 9. A method of treating a herpesviral infection of an eye, the method comprising the step of topically administering to the eye a therapeutically effective amount of a ranpirnase.
 10. The method according to claim 9, wherein the ranpirnase is a recombinant ranpirnase.
 11. The method according to claim 9, wherein the ranpirnase is SEQ ID NO: 1 or SEQ ID NO:
 2. 12. The method according to claim 9, wherein the herpesviral infection is the cause of chorioretinitis, viral keratitis, viral conjunctivitis, or cytomegalovirus retinitis.
 13. The method according to claim 9, wherein the herpesviral infection is caused by an type I Herpes simplex virus, human cytomegalovirus, or Herpes zoster virus.
 14. The method according to claim 9, wherein the ranpirnase is formulated as an ophthalmic pharmaceutical composition.
 15. The method according to claim 14, wherein the ophthalmic pharmaceutical composition is a solution, a suspension, a nanosuspension, an emulsion, a microemulsion, a nanoemulsion, an ointment, a gel, a hydrogel, liposomes, niosomes, nanoparticles, or dendrimers.
 16. The method according to claim 14, wherein the ophthalmic pharmaceutical composition further comprises a pharmaceutically acceptable carrier and/or a pharmaceutically acceptable excipient.
 17. The method according to claim 9, wherein the ranpirnase is administered as eye drops.
 18. The method according to claim 9, wherein the eye is a human eye.
 19. A pharmaceutical composition comprising: a. a therapeutically effective dose of a ribonuclease that is a member of the ribonuclease A superfamily and that is non-irritating to an eye as determined using i. the Globally Harmonized System of Classification Evaluation Criteria and ii. the European Economic Community Ocular Evaluation Criteria; and b. a vehicle.
 20. The pharmaceutical composition of claim 19, wherein the ribonuclease is selected from a group consisting of: a. ranpirnase; b. the '805 variant; c. Amphinase 2; and d. rAmphinase
 2. 21. The pharmaceutical composition of claim 19, wherein the ribonuclease is the functional equivalent of a ribonuclease selected from a group consisting of a. ranpirnase; b. the '805 variant; c. Amphinase 2; and d. rAmphinase
 2. 22. The pharmaceutical composition of claim 19, wherein the ribonuclease is ranpirnase present in an amount of 0.1%.
 23. The pharmaceutical composition of claim 19, formulated for topical administration to the eye.
 24. The pharmaceutical composition of claim 23, wherein the composition is formulated as a solution, a suspension, a nanosuspension, an emulsion, a microemulsion, a nanoemulsion, an ointment, a gel, a hydrogel, liposomes, niosomes, nanoparticles, or dendrimers.
 25. The pharmaceutical composition of claim 19, wherein the pharmaceutical composition further comprises a pharmaceutically acceptable carrier and/or a pharmaceutically acceptable excipient. 